Extensible frame for hydraulic jacks



United States Patent [111 3,549,125

[72] Inventor David Hamilton 2,363,752 11/1944 Scott 254/ 1X 401 N. Bryan, Weatherford, Okla. 73096 [211 App]. No. 761,191 Primary ExaminerRobert C. Riordon [22] Filed Sept. 20,1968 Assistant Examiner-David R. Melton [45] Patented Dec. 22, 1970 Attorney-Krafft and Wells [54] EXTENSIBLE FRAME FOR HYDRAULIC JACKS 4 Claims, 4 Drawing Figs.

ABSTRACT: An extensible frame for a hydraulic ack particu- [52] 254/86 larly suitable for lifting trailers, wherein the frame comprises 254/1 an elongated housing containing a telescopically extensible [5 1] Int. Cl. B605 9/02 tube, i tube having a supporting leg at one end and a base no 86, at the other end to the jack is ecured bolts A sta 133-1; 248/3 54; 280/1505 tionary rod is mounted in the housing and serves as a guide for a coiled spring surrounding the stationary rod. The coiled [56] References Cited spring is compressed when the jack is actuated and urges the UNITED STATES PATENTS extensible tube into the housing when the jacking pressure is 1,570,226 l/l926 Bosco 254/ 133.1UX released.

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INVENTOR Daz e- Hami/fon BY b 2U 77 ATTORNEYS EXTENSIBLE FRAME FOR HYDRAULIC JACKS BACKGROUND OF THE INVENTION The field of the invention, is fluid pressure pushing and pulling instruments.

The state of the prior art is best illustrated by U.S. Pat. No. 2,314,589 of Mandl, which issued March 23, 1943. The patent of Mandl is particularly directed to the problem of lifting aircraft wings for the repair thereof. According to the disclosure of Mandl there is a hydraulic jack having a telescopic tube at the top thereof for compensating for the varied heights of aircraft wings.

The present invention is directed to'the problems involved in separating and supporting the trailers of trailer pickups. In order to have a means for lifting the front ends of trailers, it is necessary to carry or secure a lifting device of high capacity, in the limited space allowed, to thefront of the trailer. Under ideal conditions, the jack must have a lifting capacity for great loads, be available for immediate service, and at the same time allow return of the telescoped jack to a travel position when the trailer pickup coupling is completed. The lifting jacks found on the market today either will not lift the load presented by the new type trailers, or are much too heavy and too large to fit the small space provided for the permanent attachment to the front of the trailer.

SUMMARY OF THE INVENTION y it is, therefore, an object of the present invention to provide a trailer lifting device which has great lifting capacity, an ad justable height, a minimum weight and is collapsible into a cally extensible hollowtube which is urged into position and then pinned into position to receive the lift of the hydraulic jack. The coiled spring surrounding the guide rod urges the extensible frame into travel position! BRIEF DESCRIPTION OF THE'DRAWING The invention is described more in detail with reference to thedrawing wherein: Y

FIG. 1 is a side view of the extensible frame with the hydraulic jack in operative position;

FIG. 2 is a transverse section on the line IIII of FIG. 1',

FIG. 3 is a transverse sectionon the line III-III of FIG. 1; and

FIG. 4 is a modification of the embodiment shown in the transverse section on line lV-IV of FIG. 1.

The extensible frame in which the hydraulic jack 1 is to be positioned consists essentially of an elongated open housing 2 serving as a guide frame'in which a telescopically extensible tube 3 is slidably positioned. The housing is formed of a steel channel 4 and an elongated plate 5 joined to each other at their upper ends by a headpiece 6, and at their lower ends by an angular extension 4 of the channel, and a quadrangular tubular guide piece 7.

The extensible tube 3 is slidable through the guide piece 7 into and out of the housing 2 and carries at its upper end a laterally projecting shelf 8 for supporting and securing the base of the hydraulic jack 1. The free end of the hydraulic jack rests in a ring secured to the bottom of headpiece 6. The shelf 8, for supporting and securing the hydraulic jack 1, is slidably guided in channel 4. The stationary rod extends alongside the inside of channel 4 and is surrounded by a coil spring 10 which bears against the bottom of the shelf 8 to support the extensible tube 3 when not in use and urge tube 3 into travel position when the ressure in jack 1 is released.

The sli able bar 3 serves as a supporting leg for the extensible frame 2 and is equipped with an adjustable lower extension 11 terminating in a shoe 12. Any suitable means, such as a bolt 13, can be used to hold the extension 11' in adjusted position by insertion through the holes in extensible tube 3 and the vertically spaced holes in lower extension 11. I

In the particular embodiment shown in FIG. 4, the bolt 13 is replaced by a clamp, bracket and locking pin 14. This embodiment comprises parallel plates 17 having bolts 18 for securing the-clamp to the extensible tube 3. The bracket 16 is secured to one of the plates 17 and supports spring loaded locking pin 15. The clamp may be secured to any of the outer surfaces of extensible tube 3 and in a preferred arrangement the locking pin 15 is aligned with channel 4. The spring loaded locking pin 15, when released, drops the tube 11 to the ground and then is locked in position at the desired height. The full lift of the hydraulic jack can then lift the trailer to the height desired.

DESCRIPTION OF USING'TI-IE PREFERRED EMBODIMENT In a preferred embodiment the extensible frame is carried on a trailer by having plate 5 welded on otherwise secured in a vertical position to the front end of a trailer. The hydraulic jack 1 is carried as shown, secured to the base or shelf 8 with two bolts. The jack 1 is in closed position when not in use. In this collapsed position the hydraulic jack is bolted within the frame 2 and'is ready for fast and convenient use. The lower extension 11 is retracted into the interior of tube 3 and tube 3 is compressed upward by coil spring 10. At this point the spring loaded locking pin 15 mounted at the lower end of tube 3 affords a safe lock for travel by passing through aligning holes in the front side of tube 3 and into matching holes in tube 11. It is then a simple matter to actuate the hydraulic jack which forces the extensible tube 3 down and lifts the trailer free of the tow vehicle.

After the tow vehicle is removed, the extensible frame containing the hydraulic jack 1 serves as a landing stand. When it is desired to reconnect the trailer to the tow vehicle, the process is repeated wherein the tow vehicle is placed under the trailer and the hydraulic jack is reversed so as to lower the trailer onto the tow vehicle. The extensible frame is then urged upward by the force of the coil spring against the jack shelf base. It is very simple to release the locking pin at the lower end of the tube and lift the inside extension to the locking or travel position where the entire unit rides until needed the next time.

It will be understood that this invention is susceptible to modification in order to adapt it to different usages and conditions and, accordingly, it is desired to comprehend such modifications within this invention as may fall within the scope of the appended claims.

Iclaim:

1. An extensible frame comprising an elongated open housing and a telescopically extensible tube extending through and projecting from one end of the housing, one longitudinal wall of the housing being formed of an inwardly opening channel while the other longitudinal wall is formed of an elongated plate, a rod positioned along the open side of the channel, a shelf carried by and projecting laterally from the upper end of the extensible tube adapted to support a hydraulic jack, a coiled compression spring surrounding the rod to press upwardly against the bottom of the shelf, and a vertically adjustable leg extending into the lower end of the tube.

2. The extensible frame of claim 1, wherein said extensible tube has a rectangular cross section.

3. The extensible frame of claim 1, wherein the lower portion of said vertical adjustable leg carries a ground-engaging shoe.

4. The extensible frame of claim I, wherein said vertically adjustable leg is secured in position. by a bolt extending through said extensible tube and said adjustable leg. 

